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# In 1986, the city of Los Diablos had 20 days on which air

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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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31 May 2013, 05:34
I would say B it is. My explanation is simple. B said that new gas device was invented. What if the invention occurred somewhere 20000 Km away from this city?! The invention has nothing to do with the city.

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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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20 Jun 2013, 13:28
gmacforjyoab wrote:
BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

My initial pick was D too. But I guess after reading it the second time , I see why B makes sense.

Quote:
(B) In December of 1988 a new and far more accurate gas spectrometer was invented..

As other people have pointed out , it only says spectrometer was invented . No mention of it being used to monitor the levels.

Quote:
(D) In 1988 the mayor of Los Diablos was found to have acceptedlarge campaign donations from local industries and to have exempted those same industries from air pollution control measures. .

No doubt , the pollution increases , if mayor exempts those industries from air pollution measures. So accepting donations to exempt those industries , meant increase in air pollution. If we focus on the bold part above in D , it says in 1988 , the mayor was found to have accepted. It doesn't say that mayor ACCEPTED in 1988 and EXEMPTED the industries IN 1988. He was FOUND to have accepted in 1988. He might have accepted the donations before 1988 or in the middle of 1998 or end of 1988.They just found that thing in 1988. The exemption might have happened in 1987. Or if they found out by the end of 1988 , then exemption might have happened till they found out , in 1988. This kinda explains why the pollution increased till 1988. And mebbe once they found out in 1988 , what mayor had done , they might have reverted the exemptions , which is why in 1989 pollution went down . I know it is bit of a stretch to make these assumptions , but when we are to choose between B and D (In B - where you make an assumption that invented meant used + cant justify yet as to why did new and accurate instruments show lower pollution levels) , the assumptions what we made in D seems safer.

HTH
Jyothi

A lot of in between the line is assumed here and it sometimes blur the scope of assumption. GMAT CR options more often than not speak out to convey the clearer message. There is less of reading between the lines and more of analytical thinking.

The question stumped me as I went for D, but I personally think the question is a stretch.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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24 Jun 2013, 10:20
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BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

The question asks which one is LEAST helpful. So you should not be worried if all of the answer choices have holes in them. You want to find the answer choice that has the most # of holes and does the least in helping to explain the discrepancy that is observed.

Notice the invention occurred toward the end of 1988. This means its effect would not be seen in smog days until 1999. So a "gas spectrometer invention" would affect results in 1989, perhaps downward. There is a hole here however because it's not "for sure" that the city ended up using the gas spectrometer for that year of 1989. It's not clear that adoption followed for the city immediately after invention. So that's the first hole.

We also see that the rise between 1987-1988 is unexplained. We have some event that explains the difference between 1988 and 1989, but what about between 1987 and 1988? There is a hole here.

You'll see that these two holes are larger than the holes in the other answer choices.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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03 Jul 2013, 02:09
Let's compare B and D

clearly the ans should not give the reason why there is a increase and then decrease
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
CORRECT-Yes this new truly gives reason for decrease but not the increase
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
Wrong -This can provide a reason for increase then decrease

So B
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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03 Jul 2013, 22:46
BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
Since only invention is mentioned about the accurate gas meter, we cannot deduce whether it was used or not... SO this makes no impact on the conclusion.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
Scale was revised, don't know whether is was revised upward or downward.... This one is also tempting..

(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
Since, it is not mentioned whether the same industries made any impact on the air pollution. This can also be a good answer choice..

Please explain why B is correct and C and D are incorrect...
Please refer to my explanations above the let me know for the flaws....
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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03 Jul 2013, 23:39
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jaituteja wrote:
BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
Since only invention is mentioned about the accurate gas meter, we cannot deduce whether it was used or not... SO this makes no impact on the conclusion.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
Scale was revised, don't know whether is was revised upward or downward.... This one is also tempting..

(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
Since, it is not mentioned whether the same industries made any impact on the air pollution. This can also be a good answer choice..

Please explain why B is correct and C and D are incorrect...
Please refer to my explanations above the let me know for the flaws....

Hi jaituteja

This is a reversed question of "Resolve the paradox". It means all answers that help to explain the paradox is WRONG. The answer that does not help is CORRECT.

ANALYZE THE STIMULUS:

Fact: In 1986: the city had smog alerts on 20 days .
Fact: Early 1987, new air pollution control measures were enacted,
Fact: BUT in 1989, the number of smog alerts dropped to 16.

Note: in resolve the paradox, you will expect not to see a conclusion, JUST FACTS.

Question: Which of the following statements would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
Wrong. Because A shows in the end of 1988 the air pollution control measures actually enacted. That’s why 1989: the number of smog alerts in Los Diablos dropped to 16.
==> So A helps to explain the paradox. Hence, A is wrong

(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
Correct. Please read carefully, “Invented” differs from “applied”. The fact that "new gas spectrometer was invented" is true, but there is nothing about the city used the new gas spectrometer to measure air pollution.
==> So B does not help to explain the paradox, hence B is correct.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
Wrong. KEY point is: In early 1987, the city enacted new air pollution control measures ==> it means the city wants to reduce air pollution amount. How did the city do? One of those solutions is “revise the scale”. Do you think the city will revise the scale upward (the air pollution amount will increase). No. that's not the purpose of the city. Thus, the city will make the new scale strictrer ==> to reduce the air pollution amount as much as possible. Because of the stricter scale ==> the city had smog alerts on 39 days in 1988.
==> So C helps to explain the paradox. Hence, C is wrong.

(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
Wrong. If the city received donations from local industries to exempt those same industries from air pollution control measures. It means the "real" air pollution amount was more than the city's measure. However, air pollution amount has been monitored by gas spectrography that works independently. ==> The the number of smog alert days in 1988 increased.
==> D helps to explain the paradox. Hence, D is wrong.

(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.
Wrong. Because main air pollution – Ozone and Carbon monoxide - require a minimum of two years to break down naturally. Thus the number of smog alert day increased in 1987 and 1988, after that it decreased in 1989.
==> E helps to explain the paradox. Hence, E is wrong

Hope it helps.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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04 Jul 2013, 01:01
pqhai wrote:
jaituteja wrote:
BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
Wrong. KEY point is: In early 1987, the city enacted new air pollution control measures ==> it means the city wants to reduce air pollution amount. How did the city do? One of those solutions is “revise the scale”. Do you think the city will revise the scale upward (the air pollution amount will increase). No. that's not the purpose of the city. Thus, the city will make the new scale strictrer ==> to reduce the air pollution amount as much as possible. Because of the stricter scale ==> the city had smog alerts on 39 days in 1988.
==> So C helps to explain the paradox. Hence, C is wrong.

(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
Wrong. If the city received donations from local industries to exempt those same industries from air pollution control measures. It means the "real" air pollution amount was more than the city's measure. However, air pollution amount has been monitored by gas spectrography that works independently. ==> The the number of smog alert days in 1988 increased.
==> D helps to explain the paradox. Hence, D is wrong.

For D, how can we say that "It means the "real" air pollution amount was more than the city's measure." The option is only stating that mayor accepted donations from industries. Now, there can be two things:
Either These industries might be helping government(charity work), although the same industries were getting hampered by the control measures, and want to exempt themselves from such control measures, or These industries were the main cause of creating such huge real pollution and want to get away from the crime they have committed.
Now we are not sure whether they contributed to decrease in air pollution during the last year or not, we have no clue..
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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04 Jul 2013, 01:23
jaituteja wrote:
For D, how can we say that "It means the "real" air pollution amount was more than the city's measure." The option is only stating that mayor accepted donations from industries. Now, there can be two things:
Either These industries might be helping government(charity work), although the same industries were getting hampered by the control measures, and want to exempt themselves from such control measures, or These industries were the main cause of creating such huge real pollution and want to get away from the crime they have committed.
Now we are not sure whether they contributed to decrease in air pollution during the last year or not, we have no clue..

Hi Jaituteja.

D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.

The logic of D is: X pays money for Y, so Y will exempt X from air pollution measure.
Why X has to pay? As you said
(1) X is helping the city (charity), why X still asks Y to exempt X from air pollution measure? It make no sense.
(2) X wants to get away from the crime of creating hug real pollution, so X pays Y. It means X actually creates air pollution ==> The "real" air pollution amount is greater than It was measured.

The paradox is why air pollution in 1987 is less than that of 1988 and 1989. D explains the reason why air pollution amount in 1988 and 1989 greater than that of 1987.

Hope it helps
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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01 Oct 2013, 01:34
According to me, B option is not helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989. As per my understanding, the author needs explanation with regard to the trend or the reason for the trend in air pollution level change and not the measurement instrument.
Option B is just focusing on the instrument and not the core data.
Whereas, E option if true, is helpful in explaining the reason for the trend witnessed.

Kindly, guide.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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19 Oct 2013, 10:30
BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

IMO its D.
Question: assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

A. ok since some rules where enacted helped.
B. ok so we are measuring its accurately now which helped.
C. agh changing the scale used to determine the amount of the air pollution helped.
E. ahh to it takes 2 years which helped the cause.

D. if mayor exempted some industries does not help explain. so its a least helpful.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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20 Feb 2016, 17:32
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